A principle of lighting emitting for an organic light emitting diode OLED display is as follows: by applying certain electric fields to an anode and a cathode at two sides of an electroluminescent layer, being driven by the electric fields, electrons and holes are transferred to a light emitting layer from the anode and the cathode via an electron transport layer and a hole transmission layer respectively and encounter with each other at the light emitting layer, so as to form excitons and excite luminescence molecules. Then, the luminescence molecules emit visible lights through radiative relaxation. Compared with a transitional liquid crystal display LCD, the OLED display is increasingly applied to a field of high-performance display due to its characteristics of self-luminescent, quick response, wide viewing angle and being able to be made on a flexible substrate and so on.
The OLED can be categorized into a passive matrix driving organic light emitting diode PMOLED and an active matrix driving organic light emitting diode AMOLED according to driving modes. The traditional PMOLED generally needs to reduce driving time for an individual pixel as a size of a display device increases, and thus a transient current is needed to be increased, thereby causing a great rise of power consumption. On the contrary, in the AMOLED technique, each OLED progressively scans input current through a thin film transistor TFT switching circuit, which can solve these problems well.
However, since the AMOLED is an active driving mode, there may be charges left on a pixel capacitor at the moment of the shutdown. These charges will cause pixels, at the moment of the shutdown, to be kept at a voltage before the shutdown, so that there are residual images on the panel, thereby forming the so-called shutdown image sticking.